Reproductive isolation mechanism resulting from resolution of intragenomicconflict

Crosses have revealed the species-specific, positively correlated intensiti es of paternally expressed growth enhancer (GE) and maternally expressed gr owth suppressor (GS), which serve as a reproductive isolation mechanism in many plants and animals. However, how this mechanism evolved has remained u nanswered. A dynamic model shows that the conflict between paternally and m aternally inherited genomes may drive them to an evolutionary arms race" of their GE and GS productions, respectively. This results in paternally expr essed GE and maternally expressed GS, and their evolutionarily stable inten sities are both decreasing functions of species-specific degree of paternit y and GE and GS production costs, thereby establishing a mechanism for post zygotic isolation.